Feasibility Study of Optically Transparent CPW-Fed Monopole Antenna at 60-GHz ISM Bands

This paper presents a feasibility study on an optically transparent planar monopole lozenge antenna at the 60-GHz industrial-scientific-medical (ISM) band. The feeding of this antenna is composed of a 50-
$\Omega$
meshed coplanar waveguide. The size of the proposed antenna is around 2.3
$\,\times\,$
2.3 mm
$^{2}$
. The transparent and conductive material used to fabricate the proposed antenna is made of a gold grid layer deposited on a 0.2-mm-thick fused silica 7980 Corning substrate. The theoretical transparency equals 83% with a sheet resistance of 0.44
$\Omega$
/sq. The simulated and measured results of the transparent monopole antenna are compared to a nontransparent (but identical) antenna. It was found that both antennas have the same performances in terms of bandwidth, radiation pattern, and gain. The measurements show the same behavior for transparent and nontransparent antennas. These results confirm the absence of ohmic and skin depth losses in the gold grid layer at 60-GHz ISM bands and provide the possibility of implementing transparent antennas with performances absolutely identical to the nontransparent ones, with the advantage of a soft visual impact.